Identification and Characterizations of the Basal Sulfate-Bearing Stratum, Northern Mount Sharp, Mars

Abstract:

The Curiosity Rover during ascent of Aeolis Mons (Mount Sharp) has characterized numerous terrains and smectite-bearing strata in Glen Torridon, just to the north of the sulfate-bearing strata that overlie rocks exposed in Glen Torridon. We used a combination of HiRISE images with 0.25 m/pixel resolution, 1 m/pixel elevation data derived from HiRISE stereo pairs, and CRISM hyperspectral imaging data processed to single scattering albedos at 12 m/pixel to identify and characterize the sulfate-bearing unit that directly overlies the Glen Torridon smectite-bearing strata. This work includes generating a detailed geomorphic map, and retrieval and characterization of spectra for the basal sulfate-bearing unit. This unit outcrops to the west and east of the Greenheugh pediment. The basal unit has a relatively high albedo and smooth surface indicative of indurated material “polished” by aeolian processes. It also has unusual 0.45 to 2.65 µm spectral characteristics retrieved from CRISM FRT0000B6F1 and ATO FRT00021C92 (Along Track Oversampled) that are statistically identical for the ~150 km by 300 km wide outcrop on the western side of the pediment. The eastern outcrop shows the same spectral characteristics only in the ATO data, interpreted to be due to the limited spatial resolution of the HRL and FRT data and the relatively limited areal exposure (~120 m by 150 m) for the eastern outcrop. The spectra are consistent with the presence of basaltic materials, hydrated sulfates, and amorphous silica (2.2 µm Si-OH absorption) and are unique for the areas that Curiosity has and will be able traverse to and characterize.